The present invention relates generally to a telematic terminal which produces and edits a mixed mode document transmitted by the telematic terminal.
Comite Consultatif International Telegraphique et Telephonique (abbreviated CCITT hereinafter) gives standards for telematic services, used for a group 4 (G4) facsimile apparatus (abbreviated FAX hereinafter), teletex, and videotex, and provides various definitions about them. A mixed mode document is one of the telematic services, on the same page of which characters (and also letters) and figures are mixedly arranged but individually transmitted to a receiver terminal. Generally, the characters are converted into and transmitted as code data, and the figures are converted into and transmitted as raster data. Each page of a mixed mode document is divided into a plurality of blocks, in which the characters and figures are separately allotted, a block used for characters being called a text block, and a block used for figures being called a raster block. It is necessary to define the text block and/or the raster block before arranging the characters or the figures with a predetermined format, on a desired block.
The CCITT outlines a protocol of the mixed mode in T.501 in which values defining format are predetermined for characters and figures. That is, each of the characters and figures can be arranged in either a normal format or an abnormal format. The normal format is a mandatory format for each telematic terminal, so that the receiver terminal can always accept a mixed mode document, arranged in the normal format, received from a transmitter terminal. However, the abnormal format is optional for each telematic terminal, so that the receiver terminal can accept a character arranged in the abnormal format only when the receiver terminal is equipped with the value of the abnormal format. In this case, the characters arranged in the abnormal format can be converted into the raster data, and then transmitted to the receiver, as disclosed in Japanese Laid-Open Patent Application No. 2-56172. Incidentally, raster data of abnormal format can be converted into the normal format by the receiver terminal.
The letter interval of characters has a value in normal format of 10 letters/inch and values in abnormal format of 6, 12, and 15 letters/inch. The line interval of the characters has values in normal format of 3, 4, 6 and 12 lines/inch and a value in abnormal format of 8 lines/inch. The resolution of the raster data has values in normal format of 240 and 300 picture elements (pixels)/inch, and values in abnormal format of 200, 400, 600 and 1200 pixels/inch.
However, the conventional telematic terminal has the following disadvantages:
1. The receiver terminal cannot freely edit characters transmitted as raster data, whereas the receiver terminal can freely edit characters transmitted as code data; and
2. The communication time is long since the amount of raster data is more than that of code data;
3. When raster data is converted from abnormal format into normal format, it often exhibits deterioration; for example, the resolution with the abnormal value 400 ppi (pel per inch) is converted that with the normal value 300 ppi.
4. It is difficult for an operator of the transmitter terminal to judge which part of the mixed mode document is not receivable by the receiver terminal.